1. Field of the Invention
The present invention relates to the improvements of Goodyear's air-capsule shoes, particularly to a sole structure of Goodyear's dual-intake air-capsule shoes.
2. The Prior Arts
It is already a common sense that people, at least an outnumbered great part of them, would suffer un-comfortableness from their feet caught in a ventilation-lacked sweaty and moldy corner after wearing shoes all day long, and this is particularly true during a sultry summer day.
For improvements, an air-capsule pump has been arranged in shoes later on, such that air can be pumped out and sucked in cyclically every time the compression and expansion action of the capsule pump is performed alternately while a wearer is walking. However, in some examples, the air-capsule pump is placed outside the heel base that doesn't provide a smooth air exchange. Taiwan Patent Publication No. 371846 discloses an air-capsule pump that is arranged in a recess of heel base such that air can be pumped into the shoe through the intake for air exchange when a wearer is walking to exert a downward pressure to the sole. However, because the air-capsule pump is arranged outside the heel base, it would require a larger force to tread shoes on the floor so that air can be sucked into the shoes through the lateral air intake for air exchange that does not seem to conform to the ergonomics very much. In another prior design, the present inventor teaches an air capsule having a single intake, which is more or less insufficient in sucking airflow. For improvements, a dual-intake structure is disclosed in Taiwan Patent Application No. 91201848. As shown in FIG. 1A, in a generic Goodyear's air-capsule shoe, an external stitching is usually applied to secure an upper body 13 to a sole 11, where an insole 131 has to be introduced and nailed onto the upper body 13 before the stitching is made. Therefore, an inner peripheral strip must be stitched to the insole 131 so that the upper body 13 and the insole 131 could be fixed by steel wire and stitched with an outer peripheral strip. However, because of the inner peripheral strip, the contact area between the upper body 13 and an air capsule 12 must be lessened to result in a smaller intake-outlet volume of the capsule. Moreover, in such case, the bottom pattern of the sole 11 has to be migrated (shrunk) inwards slightly to reserve a space for the stitching. Referring also to FIG. 1B, due to the inward migration of the heel 111 of the sole 11, an inward migration corridor 114 surrounding the whole bottom face of the sole 11 peripherally is formed. Hence, as indicated in FIG. 2, in addition to the unsightliness of a small heel, a pair of shoes like this would make a wearer feel unreal when treading the floor. Then, another improvement was made to permit no inward migration of the heel 111 of the sole 11 as shown in FIG. 3, in which a linear recess 22 is entrenched partly in a heel 21 to ensure the manner of keeping stitching an upper body 26 and a sole 25 together by using an external stitching 24. Taiwan Patent Application No. 93200057 discloses such an improvement. Though, it is possible for the sole 25 to accommodate a larger air capsule whatsoever, there is still a defect pending remedy that may cause obstacle or choke during burr trimming or grinding in a rear-stage process because air intakes 23 are opened on both sides of the heel 21.